code: def test_cache_helpers_with_alternative_io(self):
      class LocalSink(beam.PTransform):
          def __init__(self, path):
              self._path = path
  
          def expand(self, pcoll):
              def write_to_file(value):
                  tf.io.gfile.makedirs(self._path)
                  with open(
                      os.path.join(self._path, "cache"), "wb"
                  ) as f:
                      f.write(value)
  
              return pcoll | beam.Map(write_to_file)
  
      dataset_key = analyzer_cache.DatasetKey("a")
      test_cache_dict = {
          dataset_key: analyzer_cache.DatasetCache(
              {"b": [bytes([17, 19, 27, 31])]}, None
          )
      }
      dataset_keys = list(test_cache_dict.keys())
  
      class LocalSource(beam.PTransform):
          def __init__(self, path):
              del path
  
          def expand(self, pbegin):
              return pbegin | beam.Create(
                  [
                      test_cache_dict[k].cache_dict["b"]
                      for k in dataset_keys
                  ]
              )
  
      cache_dir = self.get_temp_dir()
      with beam.Pipeline() as p:
          _ = test_cache_dict | analyzer_cache.WriteAnalysisCacheToFS(
              p, cache_dir, dataset_keys, sink=LocalSink
          )
  
          read_cache = p | analyzer_cache.ReadAnalysisCacheFromFS(
              cache_dir, dataset_keys, source=LocalSource
          )
  
          self.assertCountEqual(read_cache, [dataset_key])
          self.assertCountEqual(
              read_cache[dataset_key].cache_dict.keys(), ["b"]
          )
  
          for key in dataset_keys:
              beam_test_util.assert_that(
                  read_cache[key].cache_dict["b"],
                  beam_test_util.equal_to(
                      [test_cache_dict[key].cache_dict["b"]]
                  ),
              )
  
file_path: transform/tensorflow_transform/beam/analyzer_cache_test.py
imports: import os
  import apache_beam
  from apache_beam.testing import util
  import numpy
  import tensorflow
  from tensorflow_transform import analyzer_nodes
  from tensorflow_transform import analyzers
  from tensorflow_transform.beam import analyzer_cache
  from tensorflow_transform import test_case
label_desc: Use image node_id 6 for calling the AnalyzerCacheTest obj's underlying member method code with example usage: obj.test_cache_helpers_with_alternative_io() and returns: unknown, unknown